Photoelectrochemical systems have been known since approximately 1839, when the phenomenon of the effect of light on certain electrodes was discovered by Becquerel. A recent review of the status of the art with respect to photoelectrochemical systems is contained in the Manassen et al article appearing in Vol. 263 of Nature on Sept. 9, 1978. In this article and in the Manassen et al U.S. Pat. No. 4,064,326, there is disclosed that photoelectrochemical systems can contain a photoelectrode, a counter electrode and a storage electrode. Various other storage electrodes are disclosed in the Manassen et al article in the Journal of the Electrochemical Society of Apr. 1977.